Open Access

The population diversity of Doranthes excelsa Corrêa (Doryanthaceae) was measured from nine distinct geographic populations across eastern Australia, using random amplified polymorphic DNA (RAPD) markers. An UPGMA dendrogram of individuals was derived from squared Euclidian distances based on the Dice (1945) algorithm. Three clusters corresponding to populations at Somersby, Newfoundland and Kremnos Creek populations were found to be distinct from the remainder of the sampled individuals. A ΦST value of 0.443 indicated that a significant diversity between geographic populations existed; this appeared to be a product of geographical distance and isolation between some of the populations. (PCR = Polymerase Chain Reaction; RAPD = Random Amplified Polymorphic DNA) The results suggest that there is lesser gene flow between the‘northern’ populations (Kremnos Creek and Newfoundland) when compared to the ‘southern’ populations and that they have a significant level of genetic isolation. The two ‘northern’ populations should therefore be regarded as being of considerable value for conservation authorities and the commercial breeding sector and should be given priority for conservation. The plants there appear to exhibit a smaller phenotype but confirming this requires further quantification.